Burn-induced nitric oxide release in humans.

Nitric oxide (NO) generation in a series of 20 burn patients was studied with a novel anion exchange high-performance liquid chromatographic method for the simultaneous determination of nitrite (NO 2 - ) and nitrate (NO 3 - ), the stable metabolic endproducts of NO. The NO values within our survivor group (n = 17) were significantly altered at days 1, 6, and 12 postburn in contrast to controls (n = 23) (p ≤ 0.03). NO 2 - values were significantly depressed in both plasma and urine, whereas NO 3 - values were significantly elevated in contrast to control values (p ≤ 0.03). The ratio of NO 2 - :NO 3 - was significantly lower for burn patients versus controls in both plasma and urine (p < 0.01). The NO generation seemed in part to be dependent on the percentage of total body surface area burn, most dramatically elevated in patients with burns of 10 to 40% total body surface area. In subjects who did not survive beyond 36 hours postinjury because of irreversible shock (n = 3), the production of NO was significantly depressed in contrast to survivors and controls (p < 0.0001). However, the NO 2 - :NO 3 - ratio (0.001) was relatively unchanged, with reflection of a global depression in NO formation with no change in the individual component release. Burn injury resulted in an increased release/production of NO that in the first postburn week is maximally elevated immediately postinjury. NO release, although decreased at day 6 relative to the day 1 values, remained elevated into the second week postinjury when there was evidence for a further increase in NO production. The enhanced NO 3 - formation may well result from NO reacting with oxygen-free radicals counteracting superoxide anion-induced destruction of tissue, thereby potentially functioning as a protectant molecule.